Nanotechnology General News

The latest news from academia, regulators
research labs and other things of interest

Posted: Feb 24, 2012

Cleanfield Energy Nanowire Solar Cell Update

(Nanowerk News) Cleanfield Alternative Energy Inc. is pleased to provide a Nanowire Solar Cell collaboration update regarding its "Next Generation Solar Cell". Cleanfield, along with its partners McMaster University, Zhejiang University and Hyperion Shanghai Drive Technology Co. Ltd., were recently awarded an International Science and Technology Partnerships Program (ISTPP) grant, with an objective to further develop a new photovoltaic (PV) nanowire solar cell based on low cost substrates initially intended for the rapidly expanding concentrator photovoltaic (CPV) market.

The ISTPP funds will be used to develop a semiconductor nanowire, which will improve the efficiency and reduce fabrication costs of PV cells due to light trapping, enhanced carrier extraction, and the ability to use inexpensive substrates. This project will draw on the existing strengths of McMaster University in the fabrication of III-V compound semiconductor nanowires to advance the state-of-the-art PV and the Zhejiang University group, which have expertise in optoelectronic devices including electrode deposition and optical characterization of materials and devices.

The cost of PV devices can be reduced by replacing the single crystal substrates with thin film technology. However, the poly-crystalline nature of these thin film technologies generally results in reduced PV efficiency. To overcome these limitations, a substantial body of recent work in PV is beginning to exploit intentionally engineered nano-scale structures and the physics of reduced dimensionality to increase device performance. One of the leading contenders in the area of nanotechnology-based PV devices is semiconductor nanowires. Nanowires are one-dimensional rods, 1-5 microns in length and 10-100 nm in diameter. Nanowires are easily grown using the well-known vapour-liquid-solid (VLS) process. The rapid growth rate (up to 10 microns per hour) and lower material utilization of nanowires compared to thin film PV devices implies lower fabrication costs. In addition, nanowires can be grown on less expensive substrates as compared to the expensive germanium substrates used in current concentrator PV cells. This cost reduction will expand the concentrator PV market in solar farm and commercial roof-top applications. In collaboration with Cleanfield, McMaster has successfully developed the concept for a low cost, two-junction concentrator cell and developed the technology necessary to produce high quality nanowires. The two-junction cell will be further developed under the ISTPP project.

Cleanfield's CTO Mihail Stern explains, "Nanowires give far greater freedom to combine the optimum materials required for higher PV efficiency. One of the most relevant metrics for PV devices is the energy conversion efficiency; i.e. the efficiency with which sunlight can be converted to electrical energy. Nanowire technology (nanowire is about 100,000 times smaller than the diameter of human hair) will reduce the cost and increase the accessibility of solar panels, a leading source of renewable energy."

Cleanfield began its collaboration with McMaster on the nanowires in 2008. Under its agreement, Cleanfield retains commercialization rights regarding the exciting technology.

About Cleanfield Alternative Energy

Cleanfield is an innovative technology company focused on the research, development and distribution of renewable energy solutions for the urban environment. The company owns industry leading and proprietary inverter technologies, which it currently sells through a complete solution - a 3 kW vertical axis wind turbine. The company is also developing several advanced solar photovoltaic technologies with strategic partners.